repr: allow context pairs when calling show

use this instead of the special-case `Base.reprfull` in loading

base/loading.jl

@@ -1047,12 +1047,6 @@ function evalfile(path::AbstractString, args::Vector{String}=String[])
 end
 evalfile(path::AbstractString, args::Vector) = evalfile(path, String[args...])
 
-function reprfull(x)
- s = IOBuffer()
- show(IOContext(s, :module => nothing), x)
- String(take!(s))
-end
-
 function create_expr_cache(input::String, output::String, concrete_deps::typeof(_concrete_dependencies), uuid::Union{Nothing,UUID})
  rm(output, force=true) # Remove file if it exists
  code_object = """
@@ -1072,7 +1066,7 @@ function create_expr_cache(input::String, output::String, concrete_deps::typeof(
  write(in, """
  begin
  empty!(Base.LOAD_PATH)
- append!(Base.LOAD_PATH, $(reprfull(LOAD_PATH)))
+ append!(Base.LOAD_PATH, $(repr(LOAD_PATH, :module => nothing)))
  empty!(Base.DEPOT_PATH)
  append!(Base.DEPOT_PATH, $(repr(DEPOT_PATH)))
  empty!(Base.LOAD_CACHE_PATH)

base/strings/io.jl

@@ -151,8 +151,11 @@ end
 
 """
  repr(x)
+ repr(x, context::Pair{Symbol,<:Any}...)
 
 Create a string from any value using the [`show`](@ref) function.
+If context pairs are given, the IO buffer used to capture `show` output
+is wrapped in an `IOContext` object with those context pairs.
 
 # Examples
 ```jldoctest
@@ -170,6 +173,12 @@ function repr(x)
  String(take!(s))
 end
 
+function repr(x, context::Pair{Symbol}...)
+ s = IOBuffer()
+ show(IOContext(s, context...), x)
+ String(take!(s))
+end
+
 # IOBuffer views of a (byte)string:
 
 """